Die



March 14, 1967 w. J. SCHRENK 3,308,508

DIE

Fileci Ost. 2, 1964 2 Sheets-Sheet 1 INVENTOR. [2.9 I Wa /*er J. 6ch ren/ March 14, 1967 W. J. SCHRENK 3 DIE Filed Oct. 2, 1964 2 Sheets-Sheec 2 INVENTOR. 15 17 M/a//er J. Jc/vrenk Unitecl States Patent O Walter J. Schrank, Bay City, Mich. assignor t The Dow Chemical Company, Midland, Mich. a corporairon or Delaware Filed Oct. 2, 1964, Sex. N0. 401,093 6 Claims. (Cl. 18-14) This invention relates to an improved die, and, more particularly, relates to a die for the preparation of multilayer tubes from thermoplastic resinous material.

Freqnently, it is desired to extrude multl-layer tubes of thermoplastic resinous film. O.ftentimes, such tubes are simple in nature and contain one or two such layers. However, frequently it is desired to generate tubes from a plurality of layers and be able to vary the nnmber of such layers. Such extrusions frequently require various dies and intrieate arrangements of feed ports. Such dies are very expensive and represent a considerable capital investrnent.

It is an object of this invention to provide an improved die capable of being readily altered to provide tubular film of almost any desire'd number of layers.

A further object of this invention is to provide an extrusion head -capable of providing, by means of a simple adjstment, a tu'oe having from one to many layers or one or a plurality of thermoplastic resinous materials.

Further features and advantages of the present invention will become more apparent from the following specification taken in connection with the drawing wherein:

FIGURE 1 is a sectional view of a die in accordance with the invention;

FIGURE 2 is a view of the die body 01 FIGURE 1 taken along the line 22;

FIGURE 3 is a sectional view of the die body of FIG- URE 2 taken along the line 33;

FIGURE 4 is a sectional view of a distribution channel of the die body of FIGURE 2 taken along the line 44; and

FIGURE 5 is a sectional view of the die of FIGURE l taken along the line 5-5.

In FIGURE 1 there is illustrated a sectional view of a tnbing die in accordance with the present invention, generally designated by the reference numeral 10, the tubing die comprises a die body 11 having defined therein a generally centrally disposed aperture 12. The body 11 has a generally plate-like configuration having a first face 14 and a second face 15. Forrned within the body 11 in FIGURE 1 are first polymer discharge grooves 16 and 17. Further detail 0f the body 11 is illustrated in FIGURES 2, 3, and 4 wherein the die body defines a first polymer inlet 18 in full communication with a first polymer passageway 20. The polymer passageway 20 terminates at the junction of the first polymer distribution grooves 16 and 17 at the location 21. A second polymer entrance 23 is defined within the body 11 and is in communication with the passageway 24, which terminates on the fasse 15 in the aperture 25. A plurality of holt holes 27 are peripherally disposed Within the die body. In FIGURE 1 adjacent to the die body 11 is a first die plate 30. The die body 30 defines a generally centrally positioned aperture 31 which is coaxial with the aperture 12. A plurality of peripherally disposed apartures 32 are provided in the die plate 30 and adapted to lie in coaxial arrangement wtih the apertures 27 of the die body 11. The first die plate 30 has a first surface 34 in sealing engagement with surface 15 of body 11 and a second surface 35. Within the second surface 35 is disposed an annular recess 36 having a generally semicircular cross sectional configuration. Adjacent the second surface 35 is disposed a second generally similar die plate 37 having a first surface 38 in sealing engagernent with the surface 35 a centrally disposed opening 39 and a second surface 41. A circular recess 43 having a generally semi-circular configuration is formed in the surface 35 generally adjacent the opening 39. The annular recess 36 and the annular recess 43 in cooperative combination form a first plenum 45. The first plenum 45 is in communication with the aperture 39 by means of an annula r passageway 47 defined by the portions of the surfaces 35 and 38 generally adjacent the centrally disposed openings 31 and 39. T he surface 41 of the second die plate 37 defines an annular recess 49 having a generally semi-circular cross-sectional configuration. A third die plate 52 having a first surface 53 is disposed adjacent to and in sealing engagement with the surface 41 of the second die plate 37. The surface 53 defines a generally annular recess 55 having a generally semi-circular configuration 55. The die plate 52 defines a generally centrally disposed aperture 56. Generally adjacent the aperture 56, the surfaces 41 and 53 define an annular passageway 58 Which provides communication between a plenum 59 formed by the recesses 49 and 55 and the apertures 39 and 56. The die plate 52 has a surface 60 remotely disposed from the surface 53. The surface 60 defines a generally annular recess 62 generally adjacent the aperture 56. A fourth die plate 65 is disposed adjacent the third die plate 52. The fourth die plate 65 has a sentrally disposed aperture 66 and a first surface 67 in sealing engagement with the surface 60 generally annular cavity 68 is defined Witliin the surface 67. The annular cavities 62 and 63, in cooperative combination, form a lenum 70 and the surfaces 60 and 67 generally adjacent the apertures 56 and 66 define an annular passageway 71. The fourth die plate 65 has a surface 73 generally parallel to and remote from the surface 67. Within the surface 73 is defined a generally annular recess 74 disposed adjacent the opening 66. A fifth die plate 78 is disposed adjacent the fourth die plate 65. The die plate 78 forms a generally centrally disposed aperture 79. The die plate 78 has a first surface 81 in sealing c0ntact With the surface 73 of die plate 65. Within the surface 81 is formed a generally annular recess 82. The recess 74 and the recess 32 form a generally annular plenum 84. 'lhe surfaces 81 and 73 define a generally annular passageway 85 providing communication between the plenum 84 and the aperture 79. The die plate 78 has a surfa-ce 87 remotely disposed and generally parallel to the surface 81. Within the surface 87 is defined a generally annnlar recess 38 generally adjaeent the opening 79. Adjacent the fifth die plate 78 is a terminal die plate 90. The terminal die plate 90 has a generally centrally disposed aperture 91 and a surface 92 disposed in sealing engagement of the surface 87 of the die 131318 78. The surface 92 defines a generally annular recess 93 having a generally serni-circular cross-sectional configuration. The surfaces 87 and 92, in cooperative combination, form a generally annular passageway 95 g-enerally adjacent the openings 79 and 91. The recesses 88 and 93 form a generally annular pienum 97. The terminal die plate 90 has a surface 99 generally parallel to and remotely disposed from the surface 92. A retainer ring 101 is disposed generally adjacent the surface 99 of the terminal die plate 90 and is secured thereto by means of the bolts 103 (one shown). The retainer ring 101 has an internally projecting lip ortion 104 defining a generally inwardly facing annular recess 105. The retaining ring 101 has formed therein a plurality of holt holes 107 adapted to clear the head of a cap screw 108 (only one of such holes is shown). An external die member or plate 109 is disposed in sealing engagement With the surface 99 01 the terminal die plate 90 adjacent the experture 91. The die plate 109 has formed therein a shoulder 110 which is disposed within the recess and adjustabiy retained hy the shoulder 164. The die plate 169 forrns an outwardly fiaring aperture 111 Which terminates retnote fron1 the terminal die plate 90 in a die lip 112. Ti1e die plates 39, 37, 52, 65 and 78 forrn internal pas sageways 115 and 116 which are in communication with the plenums 45, 70 and 97 by means of the passageways 118, 119, 120, 118, 119, and 120 respectively. A third generally longitudinal passageway is formed Within the die plates 30, 37, 52 and 65 designated by the reference numeral 122. The passageway 22 is in commnnication with the plenurns 59 and 84 by means of the passageways 124 and 125. The passageways 115 and 116 are in communication with the terminal portions 01 the recesses 16 and 17 01 the die bdy 11. The passageway 122 is in cooperative cornmunication Witi1 the terminal opening of the passageway 25 Cf the die body 11. A sectional mandrel, generally designated by the reference numeral 131), is disposed within the apertures 12, 31, 39, 56, 66, 79, 91 and 111 of the die plates. The mandrei comprises a base portion 131 having a shank 132 disposed partially Within the aperture 12 cf the die body 11. A threaded portion 133 reeeives a mit 134 which serves to retain the base pertion 131 in sealing engagement with the surface 15 of the body 11. The base 131 is in sealing engagement With the portion of the first die plate defining the aperture 31. The base member 131 is reduced in diameter as it passes through the apertures 39 anti 56 to form a portion of a generally annular passageway 135. The base portion of the mandrel 131 defines an internai passageway 136 providing full communication along the axis 0f the mandrel. The portion of the base 1.31, remote from the externally threaded portion 133, defines an internally threaded recess 133. A mandrel extension 140 having a diameter about equal t0 the portion of alle mandrel containing the threaded recess 138 has an externaliy threaded portion 141 in engagement with the internally threaded ortion 138 of the base 131. The generaliy cylindrieal mandrel extension 140 has an internally threaded portion 142 remotely disposed from the externaliy threaded portion 132 and substantially coaxialiy aligned therewith. The mandrel extension 1411 has an internal passageway 144 adapted to cornmunicate Witl1 the internal passage 136 of the mandrel base 131. A mandrel head or die head 147 is disposed adjaceni the internally threaded portion 142 of the manclrel extension 1%11. The mandrel head 147 l1as an externally threaded p0i'tis-n 148 adapted to engage the internally threaded portion 142 of the mandrel extension 14%. Tl1e mandrel head 147 defines an internal passageway 149 adapted to comrnunicate with the passageway 144 of the mandrel extension 1411. Tl1e passageway 149 terminates in an opening 156 in a die .face 152 o1 the die head 147. The mandrel head147 has a generall3/kfrusto conical portion 153 remotely disposed from the threaded portion 148 generally adjacent the frusto conical portion 153 a die lip portion 154. The die 1ip portion 154, in cooperative combinatian with the die lip portion 112 of the die plate 119 forrns a generally annnlar extrusien orifice 156. The extrusion orifice 156 is in operative cornmunication Witb. the generally cylindrical annular chamoer 135 which is, in turn, in communication with the plenums 45, 59, '70, 84, 97 and the respective polymer supply sources.

In operation 01 the embodiment 01 the invention illustrated in FIGURES 1, 2, 3 and 4, a supply of a heatplastified extrudable material, such as, for instance, thermoplastic resinous materials is placed in operative cornbination With the polymer inlets 13 and 23. Thermoplastic resinous mater-ial flowing into the inlet 18 enters the passageway 20 and passes to the channels er passageways 16 and 17 and subsequently to the passageways 115 and 116 forrned in the die plates 30, 37, 52, 65 and '78. The material then flows through the passageways 118 und 118 into the lenums 45, 711 and 97 where it is extruded through the generally annular internaliy disposed veniently plugged by the use 01 metal dowel.

slots 47, 71 and into the annuiar passageway 135. Extrudable material entering the polymer passageway 23 passes through the passageway 24, out 0f the orifice 25 and into the generally longitudinally disposed passageway 122 formed within the die plates 30, 37, 52 and 65. Through the passageways 124 and into the plenums 59 and 84, the extrudable material is then discharged from the plenurns 59 and 84 through the annular passageways 53 and 85 into the annular passageway 135. The flow rate of the material entering the passageways 18 and 23 is maintained at a level suflcient to maintain streamlined flow within the annular passageway and the material forms layers as indicated in FIGURE 1 and designated by A, B, C, D, and E. The respective layers flow smoothly and evenly through the passageway 135 to the extrusion orifice 156 where they are discharged in the desired layer arrangement. By varying the quantity 01 material introduced to the passageways 18 and 23, various thickness can be obtained. Thus, the laminar fiow provides five layers of material issuing from the die wnich subsequently, if desired, may be oriented by the trapped bubble process or otl1er convenient means. The passageway formed in the mandrel by the passageways 1511, 149, 144 and 136 provides a convenient means for the addition of an inflating fiuid. Beneficially, the various die plates are 01 circnlar configurtion anal are provided with holt holes er uniformly spaced centers, that is uni forrn circurnferential spacing, which permits the die plates to be arranged in any desired configuration. Tims, 1, 2, 3, 4, 5 er even more different thermoplastic resinous components may be fed to such a die to provide almost any desired arrangernents of the cornponents. By adding additional die plates, such as the die plates 37, 65 and '78, and arranging the feed ports, any plenum nmy be placed in communication With any desired feed assage such as the feed passages 115 and 116. Advantageously, the communication passages, such as passages 118 and 119, are readily formed in a die plate and are readiiy fi1ied by brazing cr silver solder if it is desired to alter the configuration of the die. The feed p assages such as 115 and 116, are readily altered by drilling a Suitable hole in the die plate and undesired openings com- Beneficially, in construction of the die, in accordance with the invention, it is frequentiy advantageous to relieve at least one of the adjacent faces of the die plate to provide a circumferential' ga-p for the insertion cf a. tool to aid in disassembly. Dies substantially as illustrated in the accompanying drawing are found to be highly successful for preparing multi-layer laminates from thermoplastic resinous materials.

As is apparent from the foregoing specification, the apparatus of the present invention is susceptible 0f being embodied with various alterations and modifications which rnny differ particuiarly from those that have been described in the preceding specification and description.

For this reason, it is to be ful1y understood that all of the foregoing is intended to be merely illustrative and is not to be construed or interpreted as being restrictive er otherwise limiting 01 the present invention, excepting as it is set forth and defined in the hereco appended clairns.

What is claimed is:

1. A tubing die consisting essentialiy of a body portion, a plurality of die plates, each of the die plates defining a generally centrally disposed aperture, each 0f the die plates being adapted to interfit With one another and be maintained in sealing relationship, the adjacent die plates having generally annular recesses disposed adjacent the central opening, the annular recesses in adjacent dieplates defining a generally annular plenum and a generaily annular passage extending between the annular plenum and the centrally disposed a-pertures, a terminal die plate disposed remote from the body portion having defined therein an aperture coaxial with the apertures of the die plates, a fixed mandrel disposed Within the apertures of the terminal die plate and the die piates so positioned so as to define an annular extrusion orifice in cooperation with the terminal die plate, the die plates and die body forming a plurality of passageways extending through the die plates and communicating With selected plenurns.

2. An extrusion die particularly suited for the extrusion of tubular shaped articles having a plurality of layers f diverse maten'als, the die comprising a die body, the die body having defined therein a plurality of assageways so constructed and arranged so as to receive an extrudable material and distribute the extrudable material to selected locations on a mounting face of the die body, a plurality of plate-like die plates, each of the die plates defining a generally centrally disposed aperture, a first die plate adapted to engage the mounting face 0f the die body and having defined therein a plurality of passageways extending through the die plate from a first face to a second face, the first face of the die plate adapted to engage the mounting face of the die body in seaiing engagement, the second face of the die plate adapted to engage one of a plurality of die plates defining centrally disposed apertures and passageways corresponding to the passageways in the first die plate and the point of discharge in the die body to provide a communication passage through a mating stack of die plates in sealing engagernent, selected die p1ates having formed therein an annular groove generally adjacent the centrally disposed orifice mating die p1ates in face-to-face engagement defining a plenum and a generally annular extrusion slot discharging into the centrally disposed orifice, a terminal die plate having a generally centrally disposed opening, the terminal die plate forming a generally cir- Cular die lip and being in sealing engagement With the stack of die plates, a mandrel disposed Within the central openings of the various die plates and having a terminal end remote from the die body generally corresponding to the configuration of the opening in the terminal die plate and defining an annular extrusion orifice.

3. The apparatus of claim 2 wherein the mandrel defines a passageway terminating at the terminal end of the mandrel Within the area encompassed by the annular extrusion orifice on the terminal end and providing communication between a location on the die body rernote from the mounting face and the terminal end of the mandrel.

4. The apparatus of claim 2 wherein the mandrel comprises a plurality of generally cylindrical bodies secured together to form a rigid member.

5. The apparatus of claim 2 wherein the die body and die plates have a generally circular configuration.

6. The apparatus of claim 5 wherein the die piates including the terminal die plate have formed therein a plurality of holt or mounting holes having equal annular spacing.

References Cited by the Examiner UNITED STATES PATENTS 2443,053 6/1948 Parmelee 1814 X 2747223 5/ 1956 Cady. 2,820249 1/ 1958 Colombo 1813 3102303 9/1963 Lainson 1814 FOREIGN PATENTS 520,637 6/ 1953 Belgium.

537,801 3/ 1957 Canada. 1,082043 5/ 1960 Germany.

WILLIAM J. STEPHENSON, Primary Examina. 

1. A TUBING DIE CONSISTING ESSENTIALLY OF A BODY PORTION, A PLURALITY OF DIE PLATES, EACH OF THE DIE PLATES DEFINING A GENERALLY CENTRALLY DISPOSED APERTURE, EACH OF THE DIE PLATES BEING ADAPTED TO INTERFIT WITH ONE ANOTHER AND BE MAINTAINED IN SEALING RELATIONSHIP, THE ADJACENT DIE PLATES HAVING GENERALLY ANNULAR RECESSES DISPOSED ADJACENT THE CENTRAL OPENING, THE ANNULAR RECESSES IN ADJACENT DIE PLATES DEFINING A GENERALLY ANNULAR PLENUM AND A GENERALLY ANNULAR PASSAGE EXTENDING BETWEEN THE ANNULAR PLENUM AND THE CENTRALLY DISPOSED APERTURES, A TERMINAL DIE PLATE DISPOSED REMOTE FROM THE BODY PORTION HAVING DEFINED THEREN AN APERTURE COAXIAL WITH THE APERTURES OF THE DIE PLATES, A FIXED MANDREL DISPOSED WITHIN THE PAERTURES OF THE TERMINAL DIE PLATE AND THE DIE PALTES SO POSITIONED SO AS TO DEFINE AN ANNULAR EXTRUSION ORIFICE IN COOPERATION WITH THE TERMINAL DIE PLATE, THE DIE PLATES AND DIE BODY FORMING A PLURALITY OF PASSAGEWAYS EXTENDING THROUGH THE DIE PLATES AND COMMUNICATING WITH SELECTED PLENUMS. 